Message ID | 1338275765-3217-9-git-send-email-yong.zhang0@gmail.com |
---|---|
State | Changes Requested |
Delegated to: | David Miller |
Headers | show |
On 05/29/2012 12:46 PM, Yong Zhang wrote: > From: Yong Zhang <yong.zhang@windriver.com> > > 1) call_function.lock used in smp_call_function_many() is just to protect > call_function.queue and &data->refs, cpu_online_mask is outside of the > lock. And it's not necessary to protect cpu_online_mask, > because data->cpumask is pre-calculate and even if a cpu is brougt up > when calling arch_send_call_function_ipi_mask(), it's harmless because > validation test in generic_smp_call_function_interrupt() will take care > of it. > > 2) For cpu down issue, stop_machine() will guarantee that no concurrent > smp_call_fuction() is processing. > > Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> > Cc: "David S. Miller" <davem@davemloft.net> > Cc: sparclinux@vger.kernel.org > --- > arch/sparc/kernel/smp_64.c | 6 ++---- > 1 files changed, 2 insertions(+), 4 deletions(-) > > diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c > index f591598..60e745c 100644 > --- a/arch/sparc/kernel/smp_64.c > +++ b/arch/sparc/kernel/smp_64.c > @@ -124,9 +124,9 @@ void __cpuinit smp_callin(void) > while (!cpumask_test_cpu(cpuid, &smp_commenced_mask)) > rmb(); > > - ipi_call_lock_irq(); > + local_irq_disable(); This looks odd. IRQs must not have been enabled at this point. Just remove the call to local_irq_enable() that is found a few lines above this line and then you won't have to add this call to local_irq_disable(). > set_cpu_online(cpuid, true); > - ipi_call_unlock_irq(); > + local_irq_enable(); > > /* idle thread is expected to have preempt disabled */ > preempt_disable(); > @@ -1308,9 +1308,7 @@ int __cpu_disable(void) > mdelay(1); > local_irq_disable(); > > - ipi_call_lock(); > set_cpu_online(cpu, false); > - ipi_call_unlock(); > > cpu_map_rebuild(); > Regards, Srivatsa S. Bhat -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com> Date: Tue, 29 May 2012 13:31:54 +0530 > On 05/29/2012 12:46 PM, Yong Zhang wrote: > >> From: Yong Zhang <yong.zhang@windriver.com> >> >> 1) call_function.lock used in smp_call_function_many() is just to protect >> call_function.queue and &data->refs, cpu_online_mask is outside of the >> lock. And it's not necessary to protect cpu_online_mask, >> because data->cpumask is pre-calculate and even if a cpu is brougt up >> when calling arch_send_call_function_ipi_mask(), it's harmless because >> validation test in generic_smp_call_function_interrupt() will take care >> of it. >> >> 2) For cpu down issue, stop_machine() will guarantee that no concurrent >> smp_call_fuction() is processing. >> >> Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> >> Cc: "David S. Miller" <davem@davemloft.net> >> Cc: sparclinux@vger.kernel.org >> --- >> arch/sparc/kernel/smp_64.c | 6 ++---- >> 1 files changed, 2 insertions(+), 4 deletions(-) >> >> diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c >> index f591598..60e745c 100644 >> --- a/arch/sparc/kernel/smp_64.c >> +++ b/arch/sparc/kernel/smp_64.c >> @@ -124,9 +124,9 @@ void __cpuinit smp_callin(void) >> while (!cpumask_test_cpu(cpuid, &smp_commenced_mask)) >> rmb(); >> >> - ipi_call_lock_irq(); >> + local_irq_disable(); > > > This looks odd. IRQs must not have been enabled at this point. > Just remove the call to local_irq_enable() that is found a few lines above > this line and then you won't have to add this call to local_irq_disable(). Agreed. -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c index f591598..60e745c 100644 --- a/arch/sparc/kernel/smp_64.c +++ b/arch/sparc/kernel/smp_64.c @@ -124,9 +124,9 @@ void __cpuinit smp_callin(void) while (!cpumask_test_cpu(cpuid, &smp_commenced_mask)) rmb(); - ipi_call_lock_irq(); + local_irq_disable(); set_cpu_online(cpuid, true); - ipi_call_unlock_irq(); + local_irq_enable(); /* idle thread is expected to have preempt disabled */ preempt_disable(); @@ -1308,9 +1308,7 @@ int __cpu_disable(void) mdelay(1); local_irq_disable(); - ipi_call_lock(); set_cpu_online(cpu, false); - ipi_call_unlock(); cpu_map_rebuild();